a) Technical Field
The invention is directed to a process and a device for bidirectional data exchange between computer and/or control systems in which an existing real-time data image is changed via an input and is preferably visualized.
b) Background Art
Such processes are particularly suitable in the area of visualization and control system technology where data images are displayed with real-time behavior and influenced by the operator. They are of great practical importance in that they enable an efficient, process-oriented operation of computer-linked systems with low-cost, commercially available transmission devices with a simultaneous simplification of the necessary transmission procedures and improved use of existing transmission capacities.
Processes for bidirectional data exchange between computer and/or control systems in which either the transmission speed is increased or certain data are processed as preferred data (priority control) are already known. Processes for fast on-screen response in which the operator is essentially notified of an ensuing waiting period for processing his input (local echo) are also known. Current trends generally tend toward higher-capacity systems (fiber optics, multi-processors) with increasingly shorter processing and response times. Not only is it burdensome for the operator to wait for his input to be processed, but this often impedes real-time behavior and thus hampers practical management of a process, particularly in simpler computer systems. Often, the problem is not one of slow data traffic, but the simple fact that a normally fast network is momentarily overloaded and the system cannot give the operator a response within the expected time period.
For this reason the increased use of computer-linked and networked systems demands increasingly higher transmission capacities which can presently be achieved only with the most modern technology (hardware), with complicated transmission procedures (firmware, software) or with a considerable expenditure on data management. In spite of advanced techniques, the use of the most up-to-date technology in smaller and middle-sized installations is often not financially feasible. As a rule, priority-controlled transmissions are dependent on the manufacturer, are usually not open and, if not already commercially available, are likewise too expensive. However, such transmissions represent a drain on the overall transmission capacity of a system, since the more costly transmission procedure must be processed additionally although the given average transmission speed is not increased.